Re: [PATCH v2] ARM: imx: fix error handling

Emil Goode
2014-05-16T11:16:46Z

Hello Walter,

On Fri, May 16, 2014 at 12:40:19PM +0200, walter harms wrote:
>
>
> Am 16.05.2014 11:54, schrieb Emil Goode:
> > If we fail to allocate struct platform_device pdev we
> > dereference it after the goto label err.
> >
> > I have rearranged the error handling a bit to fix the issue
> > and also make it more clear.
> >
> > Signed-off-by: Emil Goode <emilgoode@gmail.com>
> > ---
> > v2: Changed to return -ENOMEM instead of ret where possible and
> > updated the subject line.
> >
> > arch/arm/mach-imx/devices/platform-ipu-core.c | 22 +++++++++++++---------
> > 1 file changed, 13 insertions(+), 9 deletions(-)
> >
> > diff --git a/arch/arm/mach-imx/devices/platform-ipu-core.c b/arch/arm/mach-imx/devices/platform-ipu-core.c
> > index fc4dd7c..68f2a4a 100644
> > --- a/arch/arm/mach-imx/devices/platform-ipu-core.c
> > +++ b/arch/arm/mach-imx/devices/platform-ipu-core.c
> > @@ -77,34 +77,38 @@ struct platform_device *__init imx_alloc_mx3_camera(
> >
> > pdev = platform_device_alloc("mx3-camera", 0);
> > if (!pdev)
> > - goto err;
> > + return ERR_PTR(-ENOMEM);
> >
> > pdev->dev.dma_mask = kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);
> > if (!pdev->dev.dma_mask)
> > - goto err;
> > + goto put_pdev;
> >
> > *pdev->dev.dma_mask = DMA_BIT_MASK(32);
> > pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
> >
> > ret = platform_device_add_resources(pdev, res, ARRAY_SIZE(res));
> > if (ret)
> > - goto err;
> > + goto free_dma_mask;
> >
> > if (pdata) {
> > struct mx3_camera_pdata *copied_pdata;
> >
> > ret = platform_device_add_data(pdev, pdata, sizeof(*pdata));
> > - if (ret) {
> > -err:
> > - kfree(pdev->dev.dma_mask);
> > - platform_device_put(pdev);
> > - return ERR_PTR(-ENODEV);
> > - }
> > + if (ret)
> > + goto free_dma_mask;
> > +
> > copied_pdata = dev_get_platdata(&pdev->dev);
> > copied_pdata->dma_dev = &imx_ipu_coredev->dev;
>
>
> the patch is fine, but what use is this copied_pdata ?
> It scope ends next line ?
>
> re,
> wh

I also thought that looked a bit odd, but copied_pdata is a temporary
pointer to platform_data of the dev struct.

dev_get_platdata looks like this:

static inline void *dev_get_platdata(const struct device *dev)
{
return dev->platform_data;
}

So I believe it's a more compact way of writing:

pdev->dev->platform_data->dma_dev = &imx_ipu_coredev->dev;

Best regards,

Emil Goode

>
> > }
> >
> > return pdev;
> > +
> > +free_dma_mask:
> > + kfree(pdev->dev.dma_mask);
> > +put_pdev:
> > + platform_device_put(pdev);
> > +
> > + return ERR_PTR(ret);
> > }
> >
> > struct platform_device *__init imx_add_mx3_sdc_fb(